Doom 3 performace as a 64-bit game (theoretically)

[Kenneth Porter]

--On Saturday, October 22, 2005 1:15 AM -0500 Jonathan Berry 
<berryja at gmail.com> wrote:

> "64 bit is not going to speed up Doom 3. In fact there may actually be
> a minor slowdown since the pointer references are all in 32 bit, which
> will mean a hit to memory bandwidth which is the real gating problem."
>
> What does "pointer references are all in 32-bit" mean?  You can
> address more virtual memory in 64-bit, which usually means that memory
> intensive programs do better.

Pointers will be 64-bit, which means that instructions that need to load 
pointers will touch more memory. Indirection gets more expensive. Without 
the greater number of registers that came with AMD64, that might have 
inflicted a noticeable performance penalty on his engine. Gamers tend to 
obsess over small improvements that programmers consider negligible, so 
that would have marketing consequences.